Thursday, December 1, 2011

Successful test for electronic contact lens

AppId is over the quotaAppId is over the quota Summary: Researchers have created a single-pixel contact lens which was tested on a live rabbit and showed no adverse effect. Hands-free information updates streamed directly across your field of vision may not be far off.

Contact lenses may one day do more than just correct vision. Recognizing their ubiquity and proclivity for bionic adaptation, researchers have been integrating into them very small circuits and LEDs for years.

The goal to create a safe and comfortable contact lens that allows for superimposed data on a wearer’s field of vision just got one step closer.

Credit: Institute of Physics

Researchers at the University of Washington and Aalto University, Finland, have built aprototype electronic contact lens and demonstrated its safety by testing it on live rabbit eyes.

The researchers report no signs of adverse side effects in a study published today in IOP Publishing’s Journal of Micromechanics and Microengineering,

“We have demonstrated the operation of a contact lens display powered by a remote radiofrequency transmitter in free space and on a live rabbit,” said lead researcher, Babak Parviz.

“This verifies that antennas, radio chips, control circuitry, and micrometer-scale light sources can be integrated into a contact lens and operated on live eyes.”

It may only be one pixel, but the bioengineers view the contact lens as a “proof-of-concept” for producing lenses with hundreds of pixels which could provide enough resolution to display short emails and text messages before your eyes. But even with one pixel, the contact lens could help people with impaired hearing or be incorporated as an indicator into computer games.

Other challenges include finding a good power source and enabling the device to work beyond a few centimeters of the wireless battery.

The in vivo rabbit tested lens contains a display which consists of a 5-millimetre-long antenna, a silicon power harvesting and radio integrated circuit, metal interconnects, insulation layers, and a 750 square micron (one-millionth of a meter) sized transparent sapphire chip containing a custom micro LED.

The team also used micro-Fresnel lenses, which are thinner and capture more light than conventional lenses, to eventually allow for an integrated multipixel display.

After testing the contact lens in free space, the researchers fitted it carefully onto the eye of a rabbit under guidelines that govern animal use in the laboratory. In addition to demonstrating the safety of the lens, the experiment also revealed that significant improvements are needed to get to fully functional, remotely powered, high-resolution displays.

Parviz, said “We need to improve the antenna design and the associated matching network and optimize the transmission frequency to achieve an overall improvement in the range of wireless power transmission.”

“Our next goal, however, is to incorporate some predetermined text in the contact lens.”